The primary goal is to develop better methods for monitoring and optimizing antiretroviral therapy using genotype resistance assays at low levels of HIV-1 viremia. Currently genotype drug resistance assays have become the standard of care in management of HIV, but these tests are unavailable at a HIV RNA level <1000 copies/ml. We hypothesize that providing information on drug resistance mutations to providers will improve clinical outcome as measured by virologic control and exposure to fewer antiretroviral agents. Also, we seek to characterize and determine the significance of intermittent low-level viremia, known as "blips." Many patients on HAART experience intermittently detectable (>50copies/mL) low-level HIV-1 viremia, raising concerns about emerging resistance and eventual treatment failure. We plan to characterize the basic frequency, durations and magnitude of "blips." Moreover, by analyzing the genotype of the virus present before, during, and after a "blip," we will be able to determine if there is evidence for evolution of resistance mutations in order to provide a scientific basis for deciding whether and how best to change therapy in persons that experience "blips."